Bulletin of the Korean Chemical Society最新文献

One of the remaining challenges in the commercialization of a highly efficient ethylene tetramerization catalyst, [1-CrCl₂][B(C₆F₅)₄] (1=iPrN[P(C₆H₄Si(Octyl)₃)₂]₂), is the generation of small amounts of polyethylene (PE). To address this issue, we explored different activator options and found that (Octyl)₃Al was the most effective choice. Building on the observation that [iPrN(PPh₂)₂]CrCl₃(THF) was not completely alkylated by the action of excess Me₃Al to form ([iPrN(PPh₂)₂]Cr(μ₂-Cl)(ClMe₂AlClAlMe₃))₂, we synthesized [ortho-(MeO)C₆H₄CH₂-η¹C:κO]₃Cr, developing a catalytic system comprising this precursor, PNP ligand 1, and [MeN(H)(C₁₈H₃₇)₂][B(C₆F₅)₄]. However, this catalytic system exhibited a long induction time (~30 min) and generated a significant amount of PE. Returning to the catalytic system of [1-CrCl₂][B(C₆F₅)₄], we successfully achieved the conversion of [(EtOH)₄CrCl₂][B(C₆F₅)₄] to [(CH₃CN)₄CrCl₂][B(C₆F₅)₄] at a large scale by designing a specialized glass apparatus. Finally, we discovered that the generation of PE could be reduced by adjusting the reaction conditions during the synthesis of [1-CrCl₂][B(C₆F₅)₄].

Cobalt(II) and copper(II) complexes supported by 4-(quinolin-2-ylmethyl)morpholine (L) were characterized, and their reactivity toward the ring-opening polymerization (ROP) of rac-lactide (rac-LA) was studied. The use of [LMCl₂]/LiOⁱPr and [LMCl₂]/LiMe (M = Co, Cu) resulted in over 95% conversion within 10 min at 25 °C. The effect of the initiating group and geometry of the metal complexes steered the heterotactic enchainment of the resultant polylactide(PLA). The Co(II)/LiMe system represents the first example of the ROP of rac-LA with high heterotactic enchainment (P_r = 0.92) with 98% conversion at 0 °C.

Solid electrolytes (SEs) play an essential role in the development of all-solid-state batteries (ASSBs) due to their exceptional ionic conductivity. However, conventional pelletized SEs with hundreds of micrometers result in highly reduced energy density and suffer from mechanical brittleness, which delay the commercialization of ASSBs. In this study, we present an innovative approach to fabricate SE membranes with perforated Al₂O₃ nanolayer-coated polyethylene (PE) separator as a mechanical supporter. Al₂O₃-coated separators exhibit better adhesion with LPSCl particles and better thermal stability. As a result, the SE membrane exhibits thickness of 35 μm while maintaining a superior mechanical tensile strength. Furthermore, when the SE membrane is applied to Li||LiNi_0.7Co_0.15Mn_0.15O₂ full-cells, stable cycling performance over 250 cycles, which is comparable to thick LPSCl pellet cell, can be achieved even with higher conductance (>150 mS). Our results highlight the potential of thin and durable SE membranes in contributing to the commercialization of ASSBs.

Metal–organic frameworks (MOFs) are actively explored as sensing materials owing to their high porosity, substantial surface area, and structural diversity, providing diverse chemical and physical properties. Their fluorescent characteristics are pivotal, enabling MOFs to function as probes for detecting specific target molecules. Unlike conventional disease diagnosis methods such as biopsies or blood collection, the detection of pathogenic biomarkers in human urine is conventional and less risky. While mass spectroscopy identifies proteins and metabolites in urine at high costs, MOF test papers offer a convenient solution. These papers confirm the existence of the target molecules through naked-eye observation upon UV light irradiation at specific wavelengths. MOF-based fluorescent probes facilitate disease diagnosis, including pheochromocytoma, toluene exposure, vitamin deficiencies, gout, hyperuricemia, cancers, body disorders, and teratogenicity, with low detection limits. This review delves into recent developments in MOF fluorescent probes, covering synthesis, emission spectra, and sensing mechanisms.

Multicomponent nanomaterials with synergistic effect were typically used to enhance the photocatalytic performance. Herein, three-component nanomaterials composed of Cu₂O, Cu, and TiO₂ were prepared using a facile method, and applied in the photocatalytic degradation reactions. The synthetic procedure involves the formation of Cu₂O nanoparticle aggregates (NPAs) followed by Cu nanoparticles growth on the surface of Cu₂O NPAs in one pot, and TiO₂ encapsulation (Cu₂O-Cu@TiO₂). The catalyst structure was characterized by x-ray diffraction, field emission-scanning electron microscopy, transmission electron microscopy, and energy-dispersed x-ray. The catalytic performance of Cu₂O-Cu@TiO₂ NPAs was evaluated through the photocatalytic degradation of 4-nitrophenol under the simulated solar light. We found that it exhibited greater activity than the Cu₂O-Cu NPAs, commercial TiO₂, and Cu₂O@TiO₂ NPAs, probably due to their synergistic interactions resulting in the effective photogenerated carrier transfer in the multicomponent nanomaterials.

A multi-resonance (MR) fluorophore exhibiting circularly polarized luminescence (CPL) holds a significant promise for enhancing the utility of organic light-emitting devices. To meet this demand, we have devised molecular dyads having azaoxaborin MR emitters based on homochiral (R)- and (S)-1,1′-bi-2-naphthol. The synthesized 12,12′-di-tert-butyl-9,9′-bi(8,8′-dioxa-4b,4′b-diaza-14b,14′b-diborafluorantheno[1,2,3-de]tetracene) products (TBNBOCz) exhibit strong blue fluorescence, with a remarkable 100% fluorescence quantum yield and an extremely narrow full width at half-maximum of 22 nm. However, unexpectedly, TBNBOCz exhibits negligible electric circular dichroism and CPL activities. Chiroptical investigations into the reaction precursors reveals an occurrence of racemization in the borylation step. This result emphasizes the importance of understanding synthetic processes and their impact on the chiroptical properties.

Rapid advancements in energy storage technology, driven by a growing demand for energy storage devices, underscore the crucial need to comprehend ionic conduction behavior. Consequently, intensive research on high-performance ionic conductors becomes imperative. Covalent organic frameworks (COFs) have emerged as invaluable materials in the realm of solid-state or quasi-solid-state ion-conduction, leveraging their unique properties such as significant porosity, tunability, and robust physicochemical durability. These distinctive attributes position COFs as promising candidates for the development of electrodes, electrolytes, and separator materials characterized by high capacities, rapid ion transport, and electrochemical stability. This review provides insights into COFs as ionic conductors, discusses recent advancements in COF-based energy storage devices, and explores the influence of structural functionalization, pore size engineering, and dimensional regulation on ionic conduction. Moreover, the review aims to deepen understanding and pave the way for future advancements in the utilization of COFs within energy storage technologies.

Amines bearing diverse aryl substituents for potential utilities as energy and new materials have been synthesized from aziridine-2-carboxaldehyde and diverse aryl-containing substrates. At first two aryl groups were to yield (aziridine-2-yl)-1,1-diaryl-methane which was converted to 5-diarylmethyl oxazolidin-2-one as a synthetic intermediate. They were further reacted with another aryl group in the presence of methanesulfonic acid to yield 2,3,3-triarylpropylamine with the possible carbenium ion intermediate. In addition, this reaction with a second additional phenolic aryl group gave rise to the diversely substituted 3-(4-methoxyphenyl)-(2,3-dihydrobenzofuran-2-yl)methanamine derived from the intramolecular aziridine ring-opening reaction by hydroxy group at phenol.

Bipyridine-based gelator 1 having two D-alanine units was prepared, and its gelation ability was evaluated in the presence of Co(NO₃)₂ and AgNO₃ in water. Gelator 1 could gelate H₂O in the presence of Co(NO₃)₂ or AgNO₃ (1.0 equiv.) in water. Gelator 1 formed a 2:1 (1:Co²⁺) octahedral complex with Co²⁺, whereas it formed a 2:1 (1:Ag⁺) tetrahedral complex with Ag⁺. The metallosupramolecular hydrogel with Co²⁺ assembled into a left-handed helical fiber, whereas that with Ag⁺ assembled into a nanorod structure. ¹H NMR and FTIR analyses revealed that π–π stacking and intermolecular hydrogen bonds acted as the driving force for the formation of the supramolecular nanoarchitectures. Furthermore, to characterize the viscoelastic properties of hydrogels, rheology experiments were conducted at 25°C, including time, strain, and frequency sweeps.

In this study, selenium nanoparticles (SeNPs) were synthesized and stabilized by reducing sodium selenite using ascorbic acid in an aqueous solution of sodium carboxymethylcellulose (Na-CMC) with a degree of substitution of 0.97 and a degree of polymerization of 810. IR-Fourier spectroscopy revealed that coordination bonds between functional groups in Na-CMC and SeNPs resulted in the development of polymer-metal complexes. UV–Vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) methods were used to determine the SeNP sizes in the structure of the nanocomposite film. Investigation of the stabilization and nonstabilization of SeNPs over several cycles has shown that the effect of the polymer matrix of Na-CMC on the stabilization of nanoparticles was achieved for 672 h, which was confirmed by the unchanged size distribution and resistance to change of the SeNPs synthesized in Na-CMC solutions.